William Ruckelshaus finishes his lunch. At intervals, he glances out the window of the EPA's executive dining room, watching planes roar away from National Airport.
Over the last hour, Mr. Ruckelshaus has made the job of EPA chief sound as easy as cleaning up a toxic waste dump with a mop and a cracked bucket. He has talked about intractable pollution problems, fierce budget battles, and balky congressmen. He has described the reign of his predecessor, Anne Burford, as ''a little glitch.''
Now he is sparring with a reporter who wants to know whether Ruckelshaus would take another job - US attorney general, perhaps - if President Reagan is reelected.
''But this one's so much fun,'' he says. Then he breaks out laughing.
Since taking over as administrator of the Environmental Protection Agency (EPA), Ruckelshaus has been a good soldier for the Reagan administration. He has taken the troubled agency out of the headlines and restored some measure of self-respect to the staff. He kept silent when his acid rain program was ambushed and dispatched by David A. Stockman, the White House budget chief.
''I can unequivocally say the environment is better off now than it was four years ago,'' he insists.
But he adds that ''we know more now about the extent of pollutants in the environment,'' knowledge that may make the public ''feel worse'' about pollution problems.
One innovation Ruckelshaus has brought to EPA is the brown-bag press luncheon. Every six weeks or so, a small group of reporters clutching sandwiches is ushered into the dining room, off Ruckelshaus' office, for an informal meal (EPA supplies potato chips) and chat.
With the election less than a month away, the environment and politics is a prime subject at this particular lunch. It is Ruckelshaus' position that the environment is not a front-rank issue in the presidential race.
Walter Mondale ''hasn't raised it that much,'' says Ruckelshaus. ''He's so far behind, he can't afford to spend time on issues that are not broad.'' Environmental issues do affect many people, but they are not ''broad'' in the sense that economic or peace issues are, he says.
In 1972, during Ruckelshaus' first tour of duty as EPA chief, he campaigned ''all over the place'' in support of Richard Nixon. This time around he is staying out of the political fray - with only a few scattered political speeches scheduled. ''They asked me (if I wanted to campaign) - I judged not to,'' he says.
Ruckelshaus has many specific pollution problems to worry about. He groans that school boards are furious about EPA requirements for removal of asbestos fibers in schools; he complains that Congress is attempting to pump more money into the Superfund for cleaning up waste dumps than the EPA can handle. But what particularly concerns him, he says, is the ''logjam'' of environmental laws waiting for reauthorization. This year only one big law - governing the creation and transport of hazardous waste - was actually passed.
''We have reached a kind of gridlock between environmentalists and some in industry,'' says Ruckelshaus. ''The result is Congress is frightened to act.'' He says he has spent much time lately thinking of ways to break that deadlock - but when pressed for details he laughs again and says something about ''after November.''
Risk assessment and management is another of Ruckelshaus' pet projects. He complains that government agencies often send out mixed signals - one saying a particular pollutant is highly dangerous, another saying it is relatively safe. ''No wonder the public is terribly confused. We need a common approach to assessing risk.''
Some critics, however, say EPA first needs to be much tougher on polluters, and that enforcement of environmental laws has fallen off drastically under the Reagan administration. ''I think we're enforcing the laws as much as we can,'' replies Ruckelshaus.
A reporter asks whether President Reagan really is a friend of the environment. This stops Ruckelshaus for a moment. ''What sort of a vicious question is that?'' he asks, laughing.